Inside pipe cutter



Nov. 21, 1939.

D. H. REED INS IDE PIPE CUTTER Filed Feb. 19, 1935 DEM/USUN H. REED.

INVENTOR.

` ATTORNEYS,

, preponderance of pressure 1sfapp11ed 1n accord- Patented Nov. 21, 1939OFFICE yINSIDE` PII3E CUTTER Dempson H. Reed, Houston, Tex. ApplicationvFebruary 19, `1935, vSerial No. '7,175` 1 3 claims. (01; 1er-0.4)

They invention relates to insidepipe cutters and particularly of thetype whereinthe cutting action of the blades can be controlled by theoperator.

The cutting of pipe inside of wells where the condition and positioningof the pipe is not known and where mud and abrasive are present.

is a diicult job at best. It istherefore necessary that a cutterbeprovided wherein the rate of .advancement of thel cutting blades mustbe accu-1A rately controlled so` that they will not take too great abite on the pipe andso that the adjustment of the cutters canzberetarded in accordano with the conditions encountered.

With the foregoing conditions in mind` it is one of the objects of theinvention to provide a.

cutting tool whereinv a differential drive mechanism is provided so thatadjustment of the cutters will be retarded. when excessive resistance.is.

encountered.

Another object of theinventionis to provide a cutting tool wherein thepressure causing advancement vof the cutters can be controlled bytheoperator and applied in a manner to obtain the proper cutting action.Another object. of the'invention is to provide a cutting tool wherein',the'cutter blades will be extended. and retracted and the operatoradvised when the blades havefreached their retracted.poksition asi anindication of the fact that the out has beencompletedand the ,bladesretracted so that the tool may be removed.

Another object of theinvention is to provide a cutting tool wherein thetool is anchored to the pipe being cut, and a variable driving;connection is provided iny combination with the anchoring means.

It is also angobject of the invention to provide. a differential drivewhich does not advance the cutters upon rotation of the tool except whena ance with the resistance encountered.

Another objectof the invention is to provide a pressure operated screwfeed for pipe'cutters.

Another object of the invention is tolprovide a mounting so that thecutter blades may be readily replaceable.

Still another object of theinvention is to pro-v vide a screw feed forpipe cutting blades which may be varied by both mechanical and uidpressures. I

Still another object of the invention is to pro--` vide a screw headand. cutter blades so that the blades will be advanced and retracted bythe continuous rotation ofthe tool in one direction.

Other and further objects of the invention'will be-readily `apparentwhen' ther following description isconsidered. in connectionwith theaccompanying drawing wherein; l y

Fig.v 1 is acentral', vertical section of the tool in assembled-.condition prior to its adjustment for being positioned in the well.

Fig. 2 shows avview somewhat similar to Fig. 1 but partly in. elevationgandl illustrating the posi- ,tioning of'. theqparts when the tool is`anchored and thev bladesbeing advanced to cutting position. Figs. 3 andl4 are; sections taken on the lines 3 -3` and 4--4 of Figi, respectively.

i Fig. `5 is avertical section of the lower part of the driving. mandrelin. combination with the driving stemandA illustrating. the manner ofthe advancing'and retractingV threaded connections.

Fig. 6; is a section taken on'the line 6-6 of Fg- 2. f ,i

As is the usual practice, a cutting tool ofthe typefherein described,isvlowered into the well bore by means of a string of pipe 2. This pipeextends to the surfaceand is-rotated in order to impart rotation' torthe cutting tool whichv isy indicated generally at 3. This toolis madeup of a body 4 which` isconnected tothe coupling 5 and which isin.turn.connected-to the pipe 2, threaded connectionslhaving.been-shown.rIv'his body 4 at its lower. end.has;thefnippleV 6 connected therewithwhich has' a head I toreceive the bearing 8 so thatv a swivel connectionis provided between the bodyf4- andther-anchorr I6, the bearing 8 beingccnined between the head-'I onv the body and the head I2v onthey anchorl0.

'Ifhe anchor l0. includesa' housing I4 for the driving mechanism andcarries the guide point 15:; which directsthe. tool into thepipe whichis tof be out.v v

Inforder thatftheftoolmay'besecurely anchored sof that'thereinayberelative rotation between the body 4 and. the anchor Ill a set of slips26 havebeenwinounted. on the beveled faces 2| of the: anchor I6. `Theslips may take any desired form and number, the presentillustrationshowing vertical teeth 22 on Some of the slips and are arranged to movein the slots 29 in the anchor housing I4.

Fig. 1 shows the `slips in retracted position whereas Fig. 2 shows theslips in pipe engaging position with the piston 25 depressed. Y

In order that the piston 25 will normally remain in the position oi Fig.1 a heavy coil spring 35 has been positioned in the chamber 26 and isconned between the control disc 3| which is positioned in the piston 25and the pressure `bearing 32 which is also in the chamber 26.A Theinitial tension on this spring tending to support the piston 25 canrbeadjusted by means of the set screws 34, a plurality of which are`threaded through the head of the piston and engaged against thepressure disc 3|. It seems obvious that springs of various strengths maybe used in accordance with the original pressure which is desired. Thepressure of the spring is effective in the controlled driving of thecutter blades as will be later explained.

When the tool is to be anchored in the pipe pressure is applied throughthe operating pipe 2 so as to cause the piston to depress and the slips23 to be moved downwardly on the beveled faces 2|. When the slips haveengaged the pipe which is to be ycut an upward pull on the operatingstring 2 tends to securely anchor the slips in position so that theanchor portion l of the tool is thereafter immovable and serves as ananchor for the driving mechanism of the cutters and to also insure thatthe cutter blades will be maintained at the same elevation during thecutting operation.

The cutter blades 4B are seen in Figs. 1 and 2 and these blades arecarried by a cutter head 4| which is arranged to be extended andretracted through an opening v42 in the body 4. It should beparticularly noted that each of the cutter heads 4| is mounted on anupstanding arm 43 which projects into an opening 44 in the cutter head.This arm. 43 is pivoted at 45 to the cutter block 45 which is mounted inthe body 4.

AThe arm 43 is free to pivot in accordance with the radial movement ofthe cutter head 4|. The rear end 53 of each of the cutter heads 4| isarranged to abut against the inclined surface 5| of the driving mandrel52, so that when the mandrel is raised it will drive the cutter head 4|and the cutter 43 outwardly.

Fig. 2 shows the cutter partly extended with the mandrel 52 partlyraised. It will be seen that the armr43 has `tilted somewhat in acounterclockwise direction about itspivot 45 `so that the heel 54thereof has moved in beneath the corner 55 of the head of the mandrel52. When, however, the cutting operation has been completed and the headoi the mandrel is lowered the cor- Vner 55 will bear against the heel 54and cause it to move outwardly which will, of course move the upper endof the arm 43 inwardly and in this manner retract the cutter.

A particular advantage of this arrangement of the cutter head 4|,mandrel 52 and arm 43, is that when the mandrel is raised to itsuppermost limit that it is possible to remove the cutter head 4| fromthe tool because the arm 43 will tilt outwardly a sufficient distance toallow its upper end to move out of the groove 44. Thus when the tool isbeing repaired or reserviced for future use the cutters may be readilyreplaced by merely running the mandrel to its uppermost position. Thisis of material advantage over the prior devices wherein the entire toolhad to be disassembled in order to replace the cutters.

The driving mechanism for the device includes 1 termediate the positionsof cutter heads 4I and fingers 43. Since fluid is pumped through thetool when in operation, as hereafter described, this constructionminimizes throttling effect at this point and also reduces abrasiveaction upon the surfaces which have sliding engagement with arms 43 andcutter heads 4|. Y

A drive stem `1t is mounted in theanchor housing lll and includes a baseportion 1|,which is arranged to seat on a shoulder 12 in the anchorportion of the device. Relative rotation of the mandrel 52 and thisstem'1il causes the cutters to advance or retract. Such relativerotation is effected by differential pressure as will be laterdescribed. It is intended that thisv head 1| will normally engageagainst the shoulder 12.

The stem 1t is threaded at 13 with a double acting reversible thread ofa type well known. It should be noted, however, that only a portion 14of the stem. issothreaded and that this portion is spaced from the head1| a predetermined distance.

The lower end 15 of the mandrel 52 is hollow and is threaded at 16 in amanner to pass over the threaded portion 14 of the stem 10.v The insideof this head 15 is best seen in Fig. 5 and contains the threads 15 tomesh with the threads 13 on the stem 1i). Upon relative rotation of themandrel and the stem in a clockwise direction the head 15 will travelupwardly because these threads will be started into engagement when thetool is set. The shoulder 11 is provided in the head 15 to be engaged bythe uppermost of the threads 13 at the Atime the lowermost thread passesthe uppermost` thread 16. This causes the opposite sides of the threadsto engage and the mandrel to reverse its direction and move downwardly.The cutters are extended and retracted by this movement. f

In order to insure that there may be a constant pressure against thishead 15 to again reverse its direction at the bottom of the movement asmallretainer spring 18 has been provided between the lower end ofthe-head on the mandrel and the head 1| on the stem as best seen inFig. 1. The rings 19 are positioned between the bearing 32 and the head`1| so that proper spacing of the parts may be had. If theY friction ofthe engagement ofthe threads 13 and 15 is greater than the tendency ofthe head 1| to remain stationary because of its seat on the shoulders12, then the stem 15 will rotate with the mandrel and there will be noadvancement of the cutters.

In order to adjust the tool for operation a slot 80 has been provided inthe base of the head 1|. A screw driver may be inserted in this slot toturn the stem withrespect to the mandrel 52 until the threads 13 and 16are just started into engagement. This movement will tend to raise thevalve 82 from its seat 83 Ain the cutter block 46, With this valveslightly open and the threads just barely engaged the tool is; thenready to be inserted in the well. When it arrives at the properelevation the pump pressure will be applied to the fluid in the pipe sothat it will pass downwardly around the valve 82,` around'the .mandrel52, andA into the top, of thefchamber 26. It will.l

then be forced through the openings 21 which is the first majorrestriction encountered. As the pressure buildsl up on the piston abovethe openings 21 the piston will be forced downwardly to move the slips28 outwardly and the tool can then be anchored by a slight pull upwardon the pipe 2=y to set the slips against the face of the pipe which isto be cut.

The downward movement of the piston r25. also increases the compressionof the spring so that a greater pressure isapplied tothe bearing S2 andthe head 1| so thatthere willbe a tendency for the head 1| togremainstationaryalong with theA anchor I0. With the parts in this position thepipe 2 and the body 4 will be rotated; the pump pressure may bemaintained or may be reduced as the operator desires yin accordance withhis practice or the-circulation may be coni tinued to wash away anymatter remaining inside of thepipe which is to be cut.

When the operator is ready to begin the cutting operation it is onlynecessary for him lto rotate the stem 2. This rotation is imparted tothe mandrel 52 by the lugs 6i so that the threads 16 are caused to bearagainst the threads 13 on the threaded portion 14 of the stem 10. l

The compression on the spring will be so adjusted by the set screws 34and the pump pressure applied by the liquid `passing through theopenings 21 in the piston 25 that the contact of the threads will not beovercome by the yresistance tov rotation of the head 1| on the shoulder12 and the driving mechanism will Arotate as a unit. When the operatorbelieves that his tool is properly anchored and the parts functioningvthen he will increase the pump pressure to further' depress the`pressure plate 3| andy increase the compression on the spring 30 andconsequently of the head 1| against the shoulder w12, When thisresistance to rotation of 1| on 124 increases to where it exceeds thatof the threaded portions the stem 18 may continue to rotate but willdrag behind the mandrel so that there will be some relative rotation tocause some upward movement of the mandrel. This differential pressurecauses the advancement ofthe cutters. If the resistance to cuttingshould increase because the cutters were feeding forward too fast or forany other reason the advancement would cease just as soon as thedifferential pressure is equaled orv exceeded. The less resistanceencountered by the cutters the faster they will be advanced because thebalance of pressure would be thrown against the head 1|. In `otherwordsV avery ne and accurate control may be had of the cutters and theyinstantly react to any upset inthe balance of pressure to either advancefaster or to cease .f

advancing at all dependent on the circumstances encountered.

Ifl the operator rotates his spring of pipe a greater number of turnsthan there are threads in the head 15 then he is aware of the fact lthat the cutters have not been driven immediately into the pipe but thathe must apply a greater pressure to obtain suiicient differential toeffect driving. There is, however, no positive unyielding force appliedto the cutters but onlyffaz, differential; pressure which-may beovercome and the cutters; cease to advance when conditions change. l A

When the differential pressure has caused the threads`16 to.` travel; tothe top of the threads 13 tl'ie511011141612:'t1-v willv be engaged toshift the contact .faces of the threads and the reverse movementr willoccur to; retract the cuttters. When the cuttersy are fullyretracted thevalve 8.2 will seat and cutoff the flow of liquid. This results installing of the pumps and the operator is aware of what has occurred andthat his cutters are retracted. The tool may then be moved to performanother cut as itis only necessary to anchor the tool again andvcontinue rotating. The small spring 18 tendsito causereversal of thecontact. faces of the threads and the mandrel will again start upwardlydependent upon the amount of differential pressure.

In many instances the tool may not be entrelycentered within the pipe.The pipe may be corrodedor bent'` soy that there is no uniform cuttingaction of the several cutters and there `may be materials adhering tothe pipe so that it is very uncommon that a uniform cutting action isobtained by the blades. In some instances the blades are fed outwardlyfaster than the cutting raction is performed so that they bite `or gougeinto the pipe. If a positive lunyielding driving action were imparted tothe. cutters they would transmitted down the mandrel 52 to the threads13 and 16, which increase in pressure will tend to rotate the head 1|with the mandrel 52 and thus reduce the driving action as a function ofthe resistance encountered. l

With the foregoing'arrarigement the operator may apply such pressure asdesired to the device in order to perform the cutting operation. .If hedesires to increase the pressure of his pumps a material amount thepressure will also build up in the' chamber 26 below thepressure plate3| because of the restricted orifices 82 in the head 1|. These orificeswill be smaller than the passages 21 or 3|' so that the operator canbuild up an additional pressure on the bearing 32 to be applied againstthe head 1|.

The very fine lcontrol obtained' by the differential balance of pressureresults in an operation of the cutter tool which has been heretoforeimpossible.

The feature of advantage in having the slips 2|) capable of operationvby fluid pressure is that in event the cut cannot be completed thefluid pressure may be'releasedand upon a slight downward movement of theentire tool the slips will be released because. of the pressure of thespring 38. This can be accomplished after the cutters havebeenretracted. It is also desirable to remove the cut-off.piece of pipeat the .same time the cutter tool is removed from the well. With thepresent tool it is only necessary to release thev tool and. raise it tothe proper elevation soy that theslips 2l]` will be located in thecut-off portion ofthe pipe. Fluid pressure can then be appliedtoxthetoolvtov reset the slips 2l) inside of the cut-off piece of pipe, or asit is generally termed in the field the iish. Once the slip has been setin rthe fish a considerable pull may be exerted with this cutting toolthe same as any Spear o'r other instrument which is lowered into welland into the fish for the pur-r pose of removing it from the well. There-setting of the slips 20 permits the use of the tool in making aplurality of cuts at different elevations, without removing the toolfrom the well.

What is claimed is:

l. An inside pipe `cutter comp-rising cutter blades, a cutter supportadapted to be anchored in the Well, a cutter body swiveled to saidsupport, a mandrel positioned to engage said cutter blades and to rotatewith said cutter body to advance and lretract the' cutter `blades uponrotation of said body, and means to advance and then retract saidmandrel upon relative rotation of said body `and support in onedirection.

2. An inside pipe cutter comprising a cutter support adapted to beanchored in the well, a cutter body swiveled to said support, cutterblades on said body, a mandrel positioned to rotate with said cutterbody to engage and advance and retract the cutter blades upon rotationof said body, means to advance and then retract said mandrel uponrelative rotation of said body and support in one direction, said meansincludinga contact with said support.

3. An inside pipe cutter comprising a cutter support adapted tovbeanchored in the well, a cutter body swiveled to said support, cutterblades carried by said body, a mandrel positioned to rotate with saidcutter body, means on the mandrel connected to said body to advance andretract the cutter blades upon rotation of said body, means to advanceand then retract said mandrel upon relative rotation of said body andsupport in one direction, said means including a contact with saidsupport adapted lto `drive only when a predetermined pressure is appliedthereto.

4. An inside pipe cutter including an anchor, a drive stem, coengagingsurfaces on said stem and anchor adapted for sliding contact, arotatable mandrel to be advanced by said stem, cutter blades, means tobe advanced by the mandrel to move said blades, and means to applypressure to said stem so that it has a tendency to drag behind saidmandrel during rotation thereof because of the friction on saidsurfaces, and means to advance the mandrel in proportion to the amountof drag.

5. A pipe cutter including an anchor, a stem therein, cutter blades, amandrel to advance said blades, a threaded connection between said stemand mandrel to cause advance of the cutters upon relative rotation disaid stem and mandrel, which are normally arranged to rotate together,and means to cause said stem to lag behind said mandrel during rotationwhereby the cutter blades will be advanced in proportion to the lag.

6. A pipe cutter including an anchor, a stem rotatably mounted therein,cutter blades, means to advance said blades, a threaded connectionbetween said stem and means to cause advance of the cutters uponrelative rotation of said stem and means, which are normally arranged torotate together, and additional means to cause said stem to lag behindsaid means during rotation whereby the cutter blades will be advanced inproportion to the lag, said additional means in cluding a spring toapply pressure.

7. A pipe cutter including an anchor, a stem therein, cutter blades,means to advance said blades, a threaded connection' between said stemand means to cause advance of the cutters upon relative rotation of saidstem and means, which are normally arranged to rotate together, andadditional means to cause said 'stem to lag behind said means duringrotation whereby the cutter blades will be advanced in proportion to thelag, said addition-al means including a piston adapted to be moved byuid pressure.

8. A pipe cutter including an anchor, a stern therein, cutter blades,means to advance said blades, a threaded connection between said stemand means to cause advance of the cutters upon relative rotation of saidstern and means, which are normally arranged to rotate together, andadditional means to cause said stem to lag behind said means duringrotation whereby the cutter blades will be advanced in proportion to thelag, said additional means including a iiuid pressure operable pistonand a spring arranged for adjustment to vary the pressure on said stem.

9. In a cutter drive mechanism for pipe cutters an anchor, a drive stemrotatably disposed therein, a stationary spring in said anchor to applypressure to said stem tending to prevent rotation, a rotatable mandrelthreaded on the stem and adapted to normally overcome the resistance ofsaid spring to rotate said stem, and means toincrease the pressure ofsaid spring so that the differential force thus obtained results in aslower rotation of said drive stem.

10. A pipe cutter including an anchor and cutter members carryingcutters, a coengaging threaded member carried by each said anchor and acutter member, and fluid pressure operated means to control the relativemovement of said coengaging members as a function of the resistanceencountered by the cutters and one of the threaded members When opposedby the fluid pressure applied to the pipe cutter.

1l. In a cutter drive mechanism for rotatable pipe cutters, a drivingconnection for said cutters, said connection being constructed andarranged so that the cutters are advanced and thereafter retracted bycontinuous rotation of said driving connection, and including a stemwith reversed threads thereon enmeshing with complementary meansrotatable with said cutters.

12. In a pipe cutter tool, a body, cutter heads movable in said body,fingers pivoted in said body adjacent said cutter heads andinterconnected with said cutter heads, a tapered mandrel movable withinsaid body to move said heads outwarly and having a portion to abut saidngers to retract said heads, said tapered mandrel having passagestherein whereby throttling and abrasion are minimized.

13. In a cutter drive mechanism for rotatable pipe cutters, cutterheads, a tapered mandrel for advancing and retracting said cutter heads,said mandrel having a sleeve portion thereon, a drive stem extendinginto said sleeve portion and intermeshing means on said stem and sleeve,said means being shaped to be engageable by relative rotation of saidstem and sleeve and to be disengaged by a continuation ofrelativerotation in the same direction whereby the cutter heads areadvanced and retracted.

DEMPSON H. REED.

